Germination temperature
Best at 20-30 °C (68-86 °F).
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Canada goldenrod is a tall perennial with plumes of small yellow flowers in late summer. Its dust-fine seed germinates on the surface in warmth, and the plant spreads fast, so grow it where it can be contained.
Best at 20-30 °C (68-86 °F).
Surface or barely covered; no deeper than 0.5 cm (1/5 in).
About 6-14 days.
Keep seed at the surface; grow in full sun or part shade.
None needed.
Best raised in trays and transplanted.
Goldenrod seed is tiny (about 4.4 million seeds per kg) and often only about half of it germinates, so sow a small pinch per cell. Mixing it with dry fine sand helps spread it evenly.
Not needed. The seed absorbs water readily.
Not needed. A 2018 study found cold storage made no difference to germination of Canada goldenrod or European goldenrod (Solidago virgaurea). Chilling is optional for old or slow seed lots.
Not needed. Seed this small is easier to sow dry.
Germination is best between 20 and 30 °C (68-86 °F) and falls off significantly below 20 °C or above 30 °C. One nursery protocol uses heat mats at 27-30 °C (80-86 °F); another runs 22 °C (72 °F) by day and 13 °C (55 °F) at night.
Press seed onto the surface or cover with a dusting of fine compost. Cover deeper than 0.5 cm (1/5 in) strongly inhibits germination.
Fine, free-draining seed compost. Outdoors goldenrod grows in most well-drained soils and colonises poor, disturbed ground.
Keep the surface constantly moist; cover the tray with clear plastic until seedlings appear, then remove it.
Seed stays at the surface, so place trays in bright light without hot direct sun.
Six to seven days on a warm bench, one to two weeks at cooler temperatures.
Thin to one or two seedlings per cell at the first true leaves, or move seedlings to individual pots about four weeks after sowing. Plants fill a pot within four to five weeks.
Move pots outdoors about two weeks before planting out. In cool climates plant out after frost; in India, plant out when the main monsoon rains ease.
Young plants form leafy stems and begin to spread by rhizomes in their first season. Plant into a bed with a buried edging or into a large container to contain them.
Cause: seed buried too deep or kept too cool. Fix: resow on the surface and keep the tray at 20-30 °C (68-86 °F).
Cause: normal for this seed, which often germinates only about 50%. Fix: sow a pinch per cell and thin later.
Cause: aggressive rhizomes that form large, dense patches. Fix: plant inside a root barrier or container, and dig out wandering shoots each spring.
Cause: wind-borne seed with a fluffy pappus. Fix: cut off flower heads after flowering, before the seed ripens (it is fully ripe about four weeks after full bloom).
Canada goldenrod is on the EPPO List of Invasive Alien Plants, is regulated in Switzerland and Estonia, and is invasive in China. Check local rules before planting, never plant it near natural meadows, woodland edges or waterways, and do not let it seed.
Full sun or part shade. Plants reach 1-2 m (3-6.5 ft), so place them at the back of a border.
Goldenrod is a vigorous perennial and needs little fertilizer. Water young plants until they are established.
Cut stems for vases when the plumes are just opening; this also stops seed from forming.
Sealed seed kept at 3-5 °C (37-41 °F) remains viable for up to five years.
Sow goldenrod on the surface in warmth and plant it where its spread can be contained.
No. Studies found no improvement from cold storage. Sow it on the surface at 20-30 °C (68-86 °F).
Canada goldenrod is invasive in much of Europe and in China. Grow it contained, cut the flower heads before seed ripens, and follow local rules.
It was probably covered too deeply or kept too cool. Cover of more than 0.5 cm strongly reduces germination.